Adequately monitoring performance of deposition processes used during electronics production (e.g., high-brightness LED production) is important to ensuring the quality of and consistency of a relatively time-intensive procedure. Various ex-situ processes may be utilized, including photoluminescence (PL) mapping and defect inspection. Under specific excitation conditions, the local photoluminescence spectrum may be indicative of what the emission spectrum will be of an LED from the measured region of a wafer once made into a device. Measured non-uniformity of a PL peak wavelength may be traced to various process conditions, including temperature variations or gradients, which may be utilized to correct undesired process conditions.
Defect inspection may be utilized to detect and monitor various defects in the wafer, including sizes/types of surface imperfections, particles, irregularities in the thickness of epi-layers, and the like, which may hamper the performance of the semiconductor material. Defect inspection may be utilized subsequent to deposition techniques, and therefore the results of a defect inspection may be utilized to detect a defect relatively early in a manufacturing process prior to assembly of a finished product.
Currently, in order to perform both PL mapping and defect detection, two separate platforms are utilized. Such a configuration presents undesired consequences including the costs associated with owning/maintaining two separate platforms, multiple steps of handling a wafer (which increases the risk of contamination to the wafers), difficulty in correlating the separate data from the separate platforms, and the time and costs associated with performing two separate monitoring techniques.
It is therefore desirable to provide a defect inspection and photoluminescence measurement system which addresses the above-mentioned limitations of using two separate platforms, sequentially or otherwise. In addition, it is desirable to provide a defect inspection and photoluminescence measurement system such that the combination of scatter data and PL data taken at the same high resolution may enable a new level of characterization and understanding of certain defect types (e.g. those relevant to the fabrication of high-brightness LEDs).